Modem bakery operations use conveyorized ovens incorporating long continuous chains supporting grids upon which bakery products in pans are transported throughout the oven for baking. The chain utilized in these ovens can be of considerable length, often greater than 1,000 feet, and since it is in the oven the majority of the time, the chain becomes very hot, rising to temperatures which are close to that of the inside of the oven, often as much as 450xc2x0 to 480xc2x0. The chain is supported on a large number of wheels running in a partially enclosed track. Each of the wheels is rotatingly mounted by a bearing and the proper operation of these wheels and bearings is critical to the efficient operation of the oven. A failure of one or more bearings causes additional loading on adjacent wheels and bearings and can cause premature wear or serious friction damage to the track material. Therefore, in order to keep the bearings operating efficiently they are lubricated by a high speed oil injector system which operates at regular intervals, typically every three to four hours.
Because the ovens are used in the preparation of food articles, only a limited number of approved lubricants can be used, and all of the available and affordable lubricants have degraded performance at oven baking temperatures, evaporating quickly or degenerating to carbon deposits which obstruct subsequent lubricant application.
The failure of the lubricant to fully penetrate and carry the lubricant to the center of the bearing causes premature bearing failure and thus higher operating costs and increased down time to repair the oven. An alternative method of lubricating the chain and bearings is accomplished by turning the oven off and allowing the chain to cool. After the chain has cooled, the wheels and bearings can be lubricated without the problem of premature evaporation of the lubricant carrier. However, this method requires extensive down time of the oven since the oven must be turned off and allowed to cool prior to lubricating the chain, and this adversely impacts the productivity of the oven.
Thus, there is a need within the industry for a new and improved method and apparatus by which such oven conveyor chains may be more effectively lubricated, in a manner such that the lubricant penetrates throughout the bearing while minimizing the down time of the oven.
One aspect of the present invention is an apparatus for conditioning conveyor chains in commercial ovens of the type having a continuous conveyor chain supported by a track for transporting bakery products through the oven. A portion of the conveyor chain and supporting track transits outside the heated area of the oven to facilitate the adding and removal of bakery products to be conveyed through the oven for baking. The conditioning apparatus includes a fan for creating a flow of cooling air, and at least one air duct having one end proximate to the fan for receiving a portion of the flow of cooling air and a second end disposed proximate the conveyor chain along the portion thereof located outside the heated baking area of the oven, at a point upstream for the lubricator, wherein the second end of the duct directs a flow of air across the conveyor chain at that point.
Another aspect of the present invention is a method of conditioning conveyor chains in commercial ovens of the type having a continuous conveyor chain including wheels and bearings and disposed in or on a fixed track for transporting bakery products through the oven. A portion of the conveyor chain and fixed track transits outside the heated area of the oven to permit the adding and removing of bakery products for baking in the oven. An automatic chain lubricator is positioned along the portion of the fixed track transiting after the cooler outside the heated area of the oven. The method comprises the steps of establishing a flow of cooling air of a lower temperature than the conveyor chain; directing the cooling air flow onto the conveyor chain while the chain is exterior to the heated area of the oven; and, at predetermined intervals, injecting a flow of lubricant into the bearings of the wheels of the conveyor chain.
These and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings.